#include<stdio.h>
void main()
{
    double a,b;
    scanf("%lf,%lf",&a,&b);
    printf("before:a = %.1f,b = %.1f\n",a,b);
    a = a + b;
    b = a - b;
    a = a - b;
    printf("after:a = %.1f,b = %.1f\n",a,b);
}